Method of jigging



Oct. 11, 1938. a. M. BIRD METHOD J IGGING Filed July 23, 1934 5 Shee 's-She et 1 [Viki/V702: BYRON M BIRD Oct. 11, 1938. B. M. BIRD METHOD OF J IGGING Filed July 23, 1934 5 Sh eets-Sheet 2 LNN NN A3 ATT'x Oct. 11, 1938. BlRD 2,132,376

METHOD OF JIGGING Filed July 23, 1934 5 Sheets-Sheet 3 ivl/f/vroe:

BYRON M. Buan Oct. 11, 1938. B. M. BIRD 2,132,376

METHOD OF JIGGING Filed July 23, 1934 5 Sheets-Sheet 5 9, a s; -m

I a 6 f g 7 Peer/4195.4 1M 8 5 fizz/V702; BYRON M. 15x21) Patented Oct. 11, 1938 METHOD OF JIGGING Byron M. Bird, Columbus, Ohio, assignor to The J eflrey Manufacturin of Ohio g Company, a corporation Application July 23, 1934,: Serial No. 736,443 In Great Britain July 24, 1933 17 Claims.

This invention relates to the art of jigging, which in general is the stratification of a bed of material resting upon a screen by means of upward pulsations of water, or alternating upward and downward pulsations of water with respect to said bed of material.

- The particular problem which this application will consider, as illustrative, is the stratification of raw coal into clean coal and refuse such as shale, bone" and pyrite. This raw material is chosen purely as illustrative and not as restrictive, for the method disclosed may be employed for the stratification of other minerals.

One object of the invention is to provide a new method of jigging by providing a new cycle of operation of the jigging fluid, both as to the period of a complete cycle employed for pulsion, and suction, and as to the particular shape of a curve representing the pulsion and suction periods, as a fluid time-velocity curve.

anism of Figs. 5 and 6 taken on the line 7-7 of Fig. 5;

r Fig. 8 is a sectional view taken on. the line,8--8 of Fig. 5; v

Figs. 9, 10 and 11 are typical time-velocity curves illustrating a single cycle of movement of the jigging fluid with respect to a sieve, accord ing to the method of my invention; and

Fig. 12 is a graphical illustration of the condition of a bed undergoing jigging according to my method at several stages of each cycle of 'operation.

The principal function of jigging is to effect a separation of different classes of materials ac- Another object of theinvention is to provide" a new and highly eflicient jigging stroke which is effective to stratify a large range of sizes of a raw coal containing impurities according to the specific gravities of its constituents.

Another object of the invention is to provide a new cycle of operation of a jigging liquid which will give a high capacity of separation for the amount of liquid used and the amount of power consumed. 7

Another object of the invention is to provide a new method of controlling the admission and exvhaustion of air under pressure to an air controlled jig and to introduce two new periods in acycle of air control thereof.

Still another object of the invention is to provide a new method of controlling the periodic condition of a bed of material undergoing a jigging operation to provide improved Stratification of the materials thereof. v

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

In the drawings:

Fig. 1 is an elevational end view of one form of apparatus which may be employed to carry out my invention, parts being shown in section;

Fig. 2 is a side elevational view of of Fig. 1 with parts shown in section;

Fig. 3 is a side elevational view of another form of apparatus which may be employed to carry out my method; 1

Fig. 4 is an end elevational view of the device of Fig. 3;

Fig. 5 is an enlarged detailed elevational view of a valve and eccentric mechanism which may be employed with the device of Figs. 1 and 2;

Fig. 6 is a sectional elevational view of the device of Fig. 5;

, Fig. 7 is a sectional view of the eccentric mech- ;cording to specific gravity found in the native state in one mass. In the art of coal cleaning, the problem is to separate the coal from the impurities found therewith, as it comes from a mine. Such impurities may be shale, bone and pyrite. Where a sized feed is employed with a jig, the problem is not unusually difficult of solution, but sizing requires considerable operation on the coal and, of course, increases the cost of cleaning thereof. It is therefore desirable to effect a stratification and classification of a. coal bed without requiring a sizing operation, or, in other words, to operate upon an unsized bedor a bed comprised of a large range of sizes. It'is here that the principal problems of stratification are presented. My method is directed particularly to a solution of these problems presented in the stratification of an unsized feed or of a feed of a large size range and provides a more complete separation of the clean coal and coal impurities than has heretofore been realized. The

method also reduces the amount of water and power necessary to effect the cleaning of the raw coal and thus presents a more efficient method than thoseheretofore in use. While my invention realizes its greatest utility and advancement in the art in the cleaning of an unsized feed, it also has certain distinct advantages when employed with a sized feed, as will hereinafter appear.

The art of jigging of minerals thereby to stratify and separate the constituent particles of a raw the device.

mineral according to the specific gravities of the separate particles, particularly by the use of w fer as a jigging fluid, is very old.

Q te generally, jigging devices comprise a sieve ,or screen for supporting the raw material, some means for cyclically forcing water upwardly through said sieve or screen and generally allowing part of said water to return back through said screen. Part of said water flows over a dam or weir and carries with it the particles of the lower specific gravity, while the particles of higher specific gravity collect on the screen or are drawn down into a hutch below the screen,

they are small enough. Some means is provided to remove the heavier particles of material accumulated on the screen, generally constituting a continuous process.

As employed in this specification and in the 5 claims, any movement of water upwardly through the sieve or screen will be a pulsion movement; thus, during each cycle of operation, there will be a pulsion period during which water moves upwardly through the sieve or screen. Any movement of the fluid downwardly through the screen will be a suction movement; thus, during any cycle of operation in which suction is used, there will be a period during which water moves downwardly through the sieve or screen. A suction stroke or period is not essential to a jigging operation and sometimes is not used. This is accomplished by supplying suflicient water to the hutch to prevent a suction stroke or period, and this may possibly be done in my method of operation.

However, as will hereinafter appear, I prefer to employ a suction stroke or period, for, in operating upon an unsized feed, it has been found to be practically essential to proper stratiflcation as it is particularly effective in separating the small particles of refuse from the larger particles of coal. V

The term mobility, as-employed in this application and in the claims is defined as that con- 7 ditipn of the bed in which all of the particles are just free to movewith' respect to each other.

Before discussing in detail the method comprising my invention, it is deemed well to first consider certain apparatus which may be em ployed to carry out said method.

Two devices are illustrated in Figs. 1, 2, 3 and 4. either of which may be employed to carry out the method constituting my invention, in its broadest aspects. The device of Figs. 1 and 2 is also particularly adapted to carry out the method of my invention in one of its more specific aspects, and that of Figs. 3 and 4 in another specific aspect.

Referring first to the device illustrated in Figs. 1 and 2, there is seen a jigging compartment comprising a tank 20 mounted between upright supports 2|, 2| carried on the base member 22 comprising a supporting frame. Projecting downwardly into the tank 20 and longitudinally dis- :posed with respect thereto is a plate 23 which, with the bottom of said tank 20, forms a U-shaped compartment providing an air chamber 24 and a washing chamber 25. Below said chambers 24 and 25 and comprising a part of the tank 20, is a hutch 26. Carried between the plate 23 and one side wall 21 of said tank 20, is a sieve 28 which may be in the form of a screen or perforate plate. Said sieve 28 is provided with reinforcing ribs 29 and, as viewed in Fig. 1, extends along a horizontal line. As illustrated in Fig.2, said sieve 28 slopes downwardly toward the right and directs '60 refuse which is collected thereon toward the refuse discharge port 229.

Adjacent the side wall 30 of the tank 20, there is provided a water inlet conduit 3| in communication with any desired source of water supply.

A hand-operated valve 32 is provided in said conduit 3| to regulate the flow of water to the hutch 26. At 33 there is seen a source of air pressure which may comprise a blower, the output of which is delivered to a pressure tank 34 by a conduit 35. From said pressure tank 34 extend individual conduits 36, one for each of the sub-compartments 31, 31, into which said tank 20 is di-- vided as by a laterally-disposed, vertically-extending plate 38. The conduits 35 may each be provided with a manually-operable control valve 39 and each has communication with the upper part of a chamber 24, individual to each of the sub-compartments 31, 31, under the control of an eccentric-operated, periodically-reciprocating valve 40. The structure details of a valve 40, which is particularly adapted to be used to carry out my method, are illustrated in Fig. 6 and will be considered more in detail hereinafter.

The plunger 4| of the valve 40 is connected by a connecting rod 42 to an eccentric mechanism 43 operated from the motor 44 through the gear reduction mechanism 45. The details of an eccentric mechanism which is particularly adapted to cooperate with the valve 40 in carrying out my method is shown in detail in Figs. 5, 6 and 7 and will be described hereinafter.

Adjacent the refuse outlet 229 is a refuse discharge chute having a pivoted pressure release plate 46. which, with a stationary guide plate 41, directs refuse from the sieve 28 to a discharge control paddle wheel valve 48. Upon rotation of said paddle wheel valve 48, under the control of the mechanism hereinafter described, measured quantities of the refuse are discharged into the refuse chamber 49 where it may be removed by a bucket-type chain elevator mechanism 50 which discharges the refuse at the port 5|. The driving chain of said elevator mechanism 59 is driven by motor 44 through the reduction gears 45 operating through a chain and sprocket mechanism 52.

In order to remove the fine particles of refuse which collect in the bottom of the hutch 26, a screw mechanism 53 is provided in the refuse sump 54 which delivers said fine particles to the refuse chamber 49 through a small door 55. Said door'55 is made just sufficiently large to allow the discharge of material from said sump 54 to said refuse chamber 49 and is maintained small in order to confine the pulsion of the jigging liquid to the said sub-compartments 31, 31 and to prevent any substantial pulsion of the fluid. in the refuse chamber 49. The mechanism for operating the refuse paddle wheel valve 48 is substantially the same as that illustrated in the device of Figs. 3 and 4 and will be described in connection with said figures. However, the driving pawl is reciprocated by a driving mechanism driven from motor 44.

The material to be jigged is fed to the device at the inlet 56 and progresses to the right, as viewed in Fig. 2 across the sieve 28 during the jigging operation. Fine refuse particles are drawn through said sieve 28 into the hutch 26 and large refuse particles collect on said plate 28 to be discharged through the refuse port 229. The jigging liquid flowing over the bailie or weir 51 carries with it the cleaned coal which is discharged at the discharge chute 58.

It is to be noted that the valves 40, for each of the sub-compartments 31, 31, are operated from a single motor 44; thus they are operated in synchronism. However, each of said valves 40 is individually adjustable and in addition the eccentric mechanism 43 for each of said valves 40 is individually adjustable. Therefore, the particular cycle of operation of each of the subcompartments 31, 31 may be individually controlled and varied at will. In addition, each of said sub-compartments 31 is provided with its individual conduit 3| and water control valve .32 whereby the amount of water of jigging fluid which is admitted to each of said sub-compartments 31 may be individually controlled. The individual valves 39, 39 provide additional indiv dual and independent control of the admission of air to the chamber 24 of each of the subcompartments 31.

Referring to Figs. 5, 6, 7 and 8, there, is disclosed an eccentric-operated valve mechanism particularly adapted to carry out my method of operation in the device illustrated in Figs. 1 and 2. However, neither the valve structure, per se, nor the eccentric structure, per se, illustrated in Figs. 5, 6, 7 and 8, is my sole invention but each is the invention of another party. As illustrated in said Figs. 5 and 6, the valve'40 comprises a cylinder 59 provided near the upper part thereof with circumferential inlet ports .60 communicating with a circumferential .chamber 6| provided with a pipe fitting 62. Adjacent the lower part of said cylinder 59 are a plurality of discharge ports 63 communicating with atmospheric pressure. The bottom'part of said cylinder 59 communicates with a belled conduit 64 forming the upperv part of the air chamber 24. The upper part of the cylinder 59 is provided with a head 65 having an integral guide sleeve 66.

Within the cylinder 59 is a pair of pistons 61 and 68. The piston 61 is adapted to control the opening andclosing of the inlet ports 68 and the piston 68 is adapted to control the opening and closing of the discharge ports 63. The piston 61 is provided with a central hub 69 and axiallyextending spokes 10. The spokes 10 permit the 'free'movement of the air received through the inlet port 60, through the. cylinder 59 to the conduit 64 and into the air chamber 24, when said piston 61 is in said inlet port opening position.

receives, tool and thus prevent its The piston '68 is also provided with a hub 1| and spokes 12in order to allow the above mentioned free passage of air through the cylinder 59.

Rigidly attached to the hub 69 is a hollow sleeve 13 adapted to be guided in the guide sleeve 66. The upper end of said hollow sleeve 13 is screwthreaded as illustrated at 14 and is adapted to screw-threadedly receive a split guide thimble 15 which may be clamped rigid thereto after having been adjusted to a desired position with respect to the threaded neck portion not said guide thimble 15. The inner cylindrical surface of said guide thimble I5 is adapted to slide on the outer surface of the guide sleeve 66. A U-shaped link l8 carrying a connecting rod 42 is pivoted to later-. ally-extending lugs 8|], 89 of the thimble 15.

Projecting through the longitudinal opening 8| of the hollow sleeve 13 is a shaft 82 rigidly attachedat its lower end with the hub H of the piston 68 and adjustably connected to the hollow sleeve I3 at its upper end by screw threads 83. A clamping nut 84 is provided for clamping said shaft 82 rigid with said hollow sleeve 13 after the former is adjusted to a desired position. To provide for the adjustment of said shaft 82 with respect to said hollow sleeve 13, the top of said shaft 82 is preferably squared as indicated at 85 whereby a wrench may be employed to rotate said shaft 82 and thereby effect its adjustment.

The portion 19 of sleeve 18 is also squared to turning with shaft 82 during its adjustment. I

As the piston 61 is rigidly attached to the hollow sleeve '13 and as the piston 68 is rigidly attached to the shaft 82, it is obvious that by rotating said shaft 82, which is screw-threaded at 88 with said hollow sleeve 18, the position of the piston 88 may be adjusted with respect to the piston 81. This adjustment may be made within wide limits and, when anydesired ad- Justment is eifected. it may be maintained by cl mping home the clamp nut 84. After said adjustment is made between said pistons 61 and 68, said pistons are adapted to move in unisonv under the control of the connecting rod 42. By virtue of the adjustability afforded by the screwthreaded connection between the threaded portion 14 of the hollow sleeve 13 and the cooperating threaded portion of the guide thimble'l5, said guide thimble 15 may be adjusted with respect to said hollow sleeve 13 and thus the positions of said pistons 81 and 68 may be adjusted for any given position of the connecting rod 42.

The upper end' of the connecting rod 42 'is connected to an eccentric mechanism 43. Said eccentric mechanism is of the variable throw type and may be of any well-known construction.

There is illustrated in Figs. 5, 6 and 7 a particular eccentric mechanism which is well adapted for use in carrying out the method of my invention, particularly in conjunction with the valve 40. Said eccentric mechanism comprises a split strap 86 rigidly connected with the connecting rod 42. -Mounted upon shaft 81 for rotation therewith, is a bushing 88 provided with a circumferential fiange'89and a cylindrical hub 98. Said hub 90 is adapted to fit into an ovalshaped. opening 9| in an eccentric plate 92, which plate is carried rigid with the bushing 88 between the fiange 8.9 and a retaining washer 93 bolted to said bushing 88. The stroke of the connecting rod 42 is, of course, controlled by the displacement of .the'axis of the eccentricthe stroke will be twice this displacement. In

order to control variably the stroke of said connecting rod 42, the eccentric plate 92 is made adjustable with respect to said bushing 88 whereby said axial displacement may be controlled at will. The oval-shaped opening 9| permits relative adjustment between said eccentric plate 92 and said bushing 88. To effect this adjustment, the flange 89 is provided with three angularly-displaced conical holes 95' adapted selectively to receive'the frusto-conical head 95 of a pin 94, the axis of which is displaced with respect to the axis of said pin 94. is adapted to be received in a drill hole in the plate 92. The axial extension 91 of said conical head 95 isscrew-threaded to receive a nut 96 and at its extremity is squared to receive a too]. By virtue of this adjusting device, the position of the bushing 88 with respect to said eccentric plate 92 may be adjustably determined and fixed in adetermined position. This is accomplished by placing head 95 in one of the three singularly-displaced holes 95' and rotating said pin about its axis to move the hub 90 of bushing 88 to any desired position in the oval-shaped opening 9| where it may be held by clamping Said pin 94v home the nut 96. As illustrated in Fig. 7, the

distance between the outer wall of the hub 99 within the oval opening 9| and the wall defining said opening 9| may be adjusted by rotation of the pin 94 about its axis. This may be efiected by a wrench fitted on the axial extension 97.

' Along the section line illustrated in said Fig. 7,

240 degrees, and place said head '95 in another 1| v follows:

conical hole. That is, plate 92 may have any one of three positions relative to bushing 88 and connecting rod 42. By this expedient, the valves of any machine, though driven from a common shaft 81, may be in place or difier by 120 or 240 degrees from any other valve. This provides for non-synchronous admission of the air to the various sub-chambers which is sometimes desirable for various reasons.

By employing the adjustable eccentric mechanism and the adjustable dual piston valve mechanism illustrated in Figs. 5, 6, '7 and 8', very flexible control of the. admission, maintenance and discharge of air under pressure to the chamber 24 is provided. The adjustable eccentrio mechanism provides for an adjustable stroke of the connecting rod 42 and a resulting adjustable stroke for the pistons 61 and 68 and for adjusting the phase relation between the two or more valves. The adjustable thimble 15 provides for an adjustable determination of the limits within which said pistons 61 and 68 will operate for any given eccentric adjustment and any given relative adjustment of pistons-61 and 68; and the adjustment provided between the shaft 82 and the hollow sleeve 13 provides an adjustment for the relative positions of the pistons 61 and 68 which, in turn, provides for the relative time of opening and closing of the inlet port 60 and the discharge ports 63. Instead of employing the eccentric mechanism 43 for operating said valve 40, I may employ a cam device and the cam surface may be given any desired configuration for operating valve 40 through any desired cycle of operation. If desired, a plurality of interchangeable cams may be provided to afford greater flexibility of operation of said valve 40.

With the valve 40 and the eccentric 43 adjusted as illustrated in Figs. and 6, and with the shaft 81 rotated in a counter-clockwise directionas viewed in Fig. 5, the cycle of operation of the admission, maintenance, and discharge of the air to the chamber 24 will be substantially as With valve 40 in the position illustrated in m. 6, both the inlet port 60 and. discharge ports 63 are closed and the chamber 24 is sealed at an initial atmospheric pressure following a period of exhaustion of chamber 24. As the shaft 81 rotates counter-clockwise and the pistons 61 and 68 are moved downward, the inlet port 60 is opened as the eccentric device '43 approaches the lower limit of its stroke. The discharge ports 63 are maintained closed through this portion of the cycle. It may be noted that as the inlet port 60 does not begin to open until the eccentric 43 has approached the downward extremity of its stroke that the rate small in comparison with what it would have been had said port started to open at approximately the instant the axis of the eccentric plate 9| passed below the axis of the shaft 81. With the.

connecting rod 42 in its extreme downward position of the stroke, the inlet port 60 will be completely opened and the discharge ports 63 will be closed. Under these conditions, the fluid under pressure would be admitted to the chamber 24 to produce upward movement of the jigging fluid through the sieve 28. On the return movement of the connecting rod 42 under the control of the eccentric 43, the inlet port 60 is closed while the outlet ports 63 are maintained closed. Under these conditions, the chamber 24 is effectively sealed under pressure and this condition is mainsaid hollow sleeve 13.

of opening of said port 50 will be limits.- In addition, the condition under tained until the connecting rod 42 has substantially completed its stroke in the upward direction under the control of the eccentric mechanism 43. When connecting rod 42 substantially completes its upward stroke, said discharge ports 5 63 are opened while the inlet port GI is maintained closed and the chamber 24 is free to exhaust at, atmospheric pressure. During the following downward movement of pistons 61 and 68, exhaust ports 63 are closed while inlet port 80 is maintained closed'and the chamber 24 is effectively sealed. This completes a cycle of operation.

In the specification and claims, the period during which inlet port 60 is open and fluid under pressure is added to the air chamber 24, is designated the inlet period. The following period during which ports 60 and 63 are both closed is designated the expansion period. The following period during which exhaust ports 63 are open is called the exhaust period and the final periodduring which ports -60 and 63 are closed under initial atmospheric pressure is called the compression period. It may be noted that with this particular valve construction, the expansion and 5 compression periods are of necessity of the same duration, while the inlet and exhaust periods may be varied within wide limits and be of difierent duration. 1

By lowering the posi on of the piston 61 with 9 respect to the connecting rod 42, the period during which the inlet port SI is maintained open may be increased and by raising said piston with respect thereto said period may be reduced. This period may be varied between wide limits, from 20 :15 degrees to 300 degrees of movement of shaft 01,

by controlling the position of said piston 61 on Likewise, by lowering the position of piston 68 with respect to connecting rod 42, the period during which the discharge ports 63 are open may be reduced and by raising said piston with respect thereto said period may be increased. This period. may also be varied between the limits above mentioned for piston 61. It is to be noted that thelength or 45 the piston 61 is such that under no condition may said piston be moved upwardly suflicient to open the inlet port 60. This requires the opening of the inlet port 60 to take place only during the downward movement of the connecting rod 42. The piston 68 is also 'of.such length and is pre!- erably so adjusted that under no condition will the discharge ports 63 be opened duringa downward movement of the connecting rod 42. That is, inlet port 60 under the control of the piston 61 is adapted to be opened only in response to a downward movement of the connecting rod 42 anddischarge ports 63 under the control of piston 88 are adapted to be opened only in response to an upward movement of the connecting rod co 42. Furthermore, the pistons i1 and i are preferably so adjusted that under no condition will operation during which inlet port 5! is opened 7 and discharge ports 64 closed may be varied-within wide limits. Likewise, the portion of during which discharge ports 63 are opened and inlet port is closed may be varied within wide which .15

IOI at Ill and is pivotally connected to the both the inlet port 50 and the discharge ports 63 are closed may be varied within wide limits and, in fact, this period may be reduced to substantially or increased to substantially 150 degrees.

It may be noted, however, that with this valve construction this period cannot exceed, even theoretically, 180' degrees and as a practical matter-the limit is probably about 150 degrees. In addition, the rate at which the ports 00 and 03 are opened or closed once their respective pistons commence an opening -or closing operation may be varied by varying the stroke of the connecting rod-42 and by varying the instant during any cycle of operation at which said opening or closing operation begins. The latter is, of course, determined to a large extent by the portion of the cycle a valve is adjusted to be opened, while the former is independently adjustable. That is, if the portion of a cycle defining the limits during which port 60, for example, first starts to open until it is totally closed, is small, such as 60 degrees, then it begins to open when eccentric 43 approaches the lower part of its stroke, during which the rate ofmovement ofpiston 61 is relatively small.

It is thus obvious that with the eccentricoperated valve structure, illustrated in Figs. 5, 6, 7 and 8, the period during which fluid is admitted to the chamber 24, the rate of this admisslon, the period during which the discharge ports 63 are opened and the-rate of opening thereof,

may each be varied within wide limits, thus providing a very flexible means for controlling the movement of the jigging fluid with respect to the sieve 20 and the consequent condition of the bed of material undergoing jigging. Y

In Figs. 3 and 4, there is illustrated another device which may be employed to carry out the method of my invention, at, least in some of its aspects. This device is similar to the device in Figs. 1 and 2 in a number of respects. The description will be directed principally to the differences between-said device and that of Figs. 1 and 2. Instead of employing air under pressure to perform the jigging operation, the device of Figs. 3 and 4 employ mechanical means for this purpose. Said device comprises a tank I00 mounted upon a frame designated generally by IN. The tank I00 is provided with a sieve I02 which is horizontal along a transverse axis of said tank and slopes downwardly to the right along a longitudinal axis thereof. Said sieve I02 may be of substantially the same construction as.

the sieve 28 in the device of Figs. 1 and 2. Said sieve leads to a refuse port I03 which is in communication with the refuse chamber I04 of substantially the same construction as the refuse chamber "illustrated in Figs. 1 and 2. The bottom of the tank I00 comprises a piston I05 flexibly connected to the bottom wall of the tank I00 by a flexible ring I06, which may be made of rubber. Said flexible ring I00 allows vibratory movement of the piston I 06 which is effective to control periodically the flow of the "jigging fluid inside of the tank illg with respect to the sieve I02. To reciprocate the piston I05, a mechanism is provided comprising a piston rod "I01 extending downwardly with said piston I05 and rigidly attached thereto as by reinforcing web s I00. Said piston rod IN is pivoted at I 09 to a lever I I0 pivoted at III and provided with an extension H2 carrying a piston II3 adapted to move upwardly against the tension of the spring H4 carried in the guide cylinder 5. A U- shaped guiding link H0 is pivoted to the frame piston rod I07 at the point 0 intermediate the ends of said piston rods I07. The jigging fluid resting on the piston I05 exerts a downward force thereon which force may be at least partially balanced by the coil spring II 4 operating through the lever H0 and its extension H2. The lever H0 is provided at its lower face with an arcuate rack H9 with which is adapted to cooperate a gear I20 carried upon the upper end of an arm Iii provided at its lower end with a roller wheel I22 adapted to ride upon the cam I23 carried on the shaft I24 which is supported to the frame IOI by bearings I26, I20. A link I2! is pivoted at I 20 at one end thereof to link I21 and at its other end is pivoted to the arm I2I at the' axis of said roller wheel I22. Said adjacent the left hand end of said rack 9, as

viewed in Fig. 3, the stroke of said piston rod I0'I will be a minimum and when it is adjacent the right" hand end'of said rack, the stroke of said piston rod will be a maximum.

Theshape of the cam I23 may, of course, be

made anything that is desired and may be made to control the operation of the piston I05 to perform the method of my invention. It the device of said Figs. 3 and A is to be operated for different cycles comprising my method, more than one cam I23 will be provided each with a different shape whereby different specific embodiments of my invention may be realized. It will,

.of course, be appreciated that the shape of the cam I23 will determine the particular shape of the curve representing the flow of fluid through the sieve I02 and by predetermining the shape of a cam any desired curve may be obtained. In this respect this particular mechanism is more flexible than that of Figs. 1 and 2 for there is no restriction on the shape of the ,cam and nothing analogous to the requirement of equal expansion and compression periods oi. the air valve thereof. As above indicated, by making a plurality of cams of different shapes, a plurality of curves may be followed. Adjustment of the ear I20 will, of course, merely control the amplitude of the stroke of a single cycle but will in no wise vary the general shape of the curve representing said cycle of operation.

An electric motor I29 driving through a. belt I30 and a V-belt variable speed mechanism I3I discharge paddle wheel valve similar to the paddle wheel valve 40 of the device of Figs. 1 and 2 which is operated under the control as a float mechanism I33 which is effective to render operative or non-operative a pawl and ratchet mechanism I34, the pawl of which is constantly reciprocating under the control of the reciproeating rod I35 connected at one end to a crank I36 geared on the shaft I24 and at the otherend to one arm of the bell crank lever I37, the other arm of which carries a pawl I38. The position of the float I33 is adapted to be determined by the refuse carried by the sieve 28 or I02. Under and I02, the float I33 is controlled and through the link I38 controls a semi-cylindrical shield I40 adapted to control the engagement or nonengagement of the pawl I38 and a ratchet wheel I4I rigidly connected to the shaft of said refuse discharge valve 48. When said refuse becomes of predetermined depth, the float I33 is lifted, thereby rotating the semi-cylindrical shield I40 in a counter-clockwise direction as viewed in Fig. 3. This removes the wall of said shield I40 which previously prevented the engagement of the pawl I38 with the ratchet wheel I. The refuse discharge valve 48 is then operated by the reciprocating pawl I38 to discharge the accumulated refuse on the sieve 28 or I02. When said refuse has been discharged or reduced to a desired level. the float I33 moves downwardly and through the link I38, rotates the shield I40 whereby it is interposed between the pawl I38 and the ratchet wheel I, thereby preventing the operation of said ratchet wheel even though the pawl I38 is continually oscillating.

A bucket-type chain elevator indicated generally by I42 is provided to lift the refuse from the elevator boot I43 and discharge it at the outlet I44.

In the operation of the device of Figs. 3 and 4, the coal to be cleaned enters the tank IOI adjacent the end I45 and is subjected to a jiggingoperation while forming a bed above the sieve I02. The refuse is discharged at the port I03 and the clean coal flows over the bailie I46 to the discharge chute I41. The fine refuse accumulated in the hutch I48 may be discharged into elevator boot I43 through an opening I48. A valve I41 is provided to control the supply of water to the hutch I48 from conduit I48.

Referring particularly to Figs. 9, 10 and. 11 of the drawings, there is illustrated three timevelocity curves which represent the velocity of the waiter flowing through a sieve or screen during a complete cycle of operation. Each of these curves illustrates the method of my invention, in one of its aspects, and illustrates a cycle of jigging operation which has been found to produce an improved and highly efilcient result.

Purely by way of illustration and not as a limitation, it may be stated that Figs. 9,. 10 and 11 represent a curve obtained with a jig of the general type illustrated in Figs. 1 and 2, with the exception that it had only one hutch compartment 3! and one air valve 40, the screen area being square foot area, the coal being %-0 bituminous or soft coal. The following table gives the other conditions of operation, for a tonnage of 2000 pounds, per hour:

the time of closing thereof. The Exhaust valve open indicates a similar condition with respect to the exhaust ports. The "Expansion-compression" column indicates the portion of each cycle during which both the inlet ports and the exhaust ports are completely closed. These periods are inherently equal. The "Stroke of valve" column is the stroke of the air valve which determines the rate of opening and the rate of closing of the inlet and exhaust ports. A 1 /2 inch stroke is indicated by curve E on Fig. 9 for this cycle of operation, in which the. size of the port at any interval of time after either the inlet or exhaust valve starts to open or close is given in square inches per square foot of screen surface. Curves E on Figs. 10 and 11 give similar indications for a 1. inch stroke and a 1% inch stroke respectively for the cycle of operation illustrated in said figures.

Fig. 12 is a graphic illustration of several conditions of a bed undergoing jigging according to my method and the various stages thereof are approximately indicated on the curves of Figs. 9, 10 and 11 by the numbers corresponding to the bed condition or stage numbers. It will, of course, be obvious that each stage merges into the next stage and no clear cut limits therebetween are possible. Furthermore, a stage may not occur at the exact location indicated on the curve but may appear at either side thereof. However, an attempt is made to illustrate with observation accuracy the limits of each stage. It "may be stated that the arrows adiacent each number represents the approximate extent of each stage.

Stage 1 is the initial stage and represents the condition of the bed with the mass of the particles resting on the sieve or screen, but with the top layers in partial suspension, which partial suspension is indicated by the particular shading there illustrated.

Stage 2 illustrates substantially the same bed condition as is illustrated by Stage 1 but with the entire bed raised to a slight extent above the sieve or screen.

Stage-8 illustrates the condition in which the top of the bed is raised still more but the bottom layers have fallen toward the sieve or screen somewhat, or in other words, are in an open condition.

Stage. 4 illustrates the condition in which the top of the bed is raised still more and the bottom layers have fallen downward, the opening of the mass of the particles having extended to approximately the center of the bed.

, Expan- Air Ex- (tlg rves Cycles it ate/rt prcs- 333g hglus 3 Stggke 0 1g. per mm. sec. sure v ve lbs./in. 2 open. gig; valve Degree: Degree: Degrm Inches 9 45 0376 2. 9 180 45 1} 10 B0 0376 2. 9 120 60 1 11 45 0376 2 9 120 120 60 1% By way of explanation, the Water" column indicates the amount of water used asexpressed in cubic feet/per second/per square foot of sieve or screen area. The "Air pressure column is the pressure in the air supply tank which remains substantially constant. The Inlet valve open" column indicates the portion of eachrcycle during which the inlet ports are opened to any extent, thus covering the time of opening and Stage 5 illustrates, the condition where the top of the bed has approached its maximum height and the bed is almost entirely open.

Stage 6 illustrates the condition of full mobility of the bed, where it is entirely open.

Stage 7 illustrates the bed condition in which the bottom thereof has closed but the greater part Stage 8 illustrates of-the top is still open.

the condition in which the top part is still open.

Stage 9 illustrates the final stage in a cycle of operation, in which the bed is entirely closed.

The several stages, as above illustrated, are representative of the average bed condition during a cycle of operation in which the bed is constantly receiving raw coal and discharging finished products; that is, underfull operating conditions.

In Figs. 9, 10 and 11, there is illustrated three time-velocity curves A which represent the rate of flow of the jigging fluid with respect to a sieve or screen carrying a bed of material subject to a jigging operation. Each of these curves is representative of my method and each has been found to produce an improved stratification of materials. Of the three curves, that represented by Fig. 9 is preferred, thoughno great difierence appears to be found between the results of the three. may be obtained by any desired apparatus, as, for example, the apparatus of Figs. 1 and 2 or that of Figs. 3 and 4. There is illustrated at B in each of said Figs. 9, 10 and 11 a typical pressure curve which represents the air pressure in the chamber 24 when a jig of the general type illustrated in Figs. 1 and 2 is employed. There is also illustrated at F in Fig. 9 a wave curve, or a.

curve which is theintegral of curve A. 'This curve represents the developed surface of a cam which should be employed to obtain curve A when a device like that of Figs. 3 and 4 is employed. That is, the entire curve represents 360 degrees of a cam and at spaced radial points the cam radius above a given base is given by the curve height. The zero ordinate of said curve represents the shortest radius of the cam and the maximum point represen s the longest radius thereof. It is obvious that by a similar integration of curves A of Figs-10 and 11, similar developed cam surfaces may be obtained.

In addition, purely for comparison, there is illustrated two sine waves, of half a cycle each, one, C, for the pulsion period and one, D, for the suction period for each curve A, to form a basis for discussion of said curves A. Each of these sine curves has the same maximum ampliture, in absolute value, as the corresponding pulsion or suction period and has the same base as its corresponding pulsion or suction period thus representing the same time interval as said period. It may be stated, that in the specification and claims any relative or comparative term or expression employed in describing either a pulsion or a suction period has as areference the half cycle of sine curve associated therewith. For example, if it is stated that the pulsion period has a small rate of increasing velocity during part of a period, it is meant that this rate of increase of velocity is small as compared with the increase in velocity represented by said sine Wave as a time-velocity curve at the same instant or over'the same period of time.

Referring to Figs. 9, 10 and 11, there is indicated by the several stage numbers along line G-G the periods of each cycle during which the several bed conditions illustrated in Fig. '12 are realized. It is to be distinctly understood that these conditions are approximate as to time, and certain of them may vary appreciably from the positions indicated. It is also to be. understood that they'are not sharply defined, but merge, one into the other. However, the representation given is in accordance with the best obtainable The curves A of these Figs. 9, l0 and 11 observations from actual operation. Referring to Figs. 9, l0 and 11 and without consideration of the bed conditions. comparison of the pulsion period of curve A with the half cycle of sine wave C which has the same maximum amplitude and same base, or time period is facilitated by dividing the total time of this period into four equal time periods indicated as a, b, c and d. Similarly, comparison of the suction period of curve A with the half cycle of sine wave D which has the same absolute maximum amplitude and same base or time period is facilitated by dividing the total t e of this period into four equal time periods indicated as e, f, g and h. With reference to Fig. 9 and considering first the pulsion period, during the first part of period a, curve A rises at a ra e less rapid than the sine curve C, or, stated in a different manner, the magnitude of the velocity is less than that of the sine curve C. In period b, the velocity is less than that of sine curve C while the slope is greater.- The maximum amplitude of curve A and the sine curve C appear at substantially the same time. In periods a and d, the velocity is less than that of the sine curve C and the slope of curve A is greater than that of sine curve C except for .the last half of period it in which the slopeis ing period 1, curve A reaches its maximum value and changes its slope from negative to positive, also crossing the sine curve D. During eriods gr and h, curve A has a velocity less than the sine curve and has a particularly pronounced change in slope near-the end of period :7 with a velocity and slope much smaller than the sine curve D during period it. It may be stated that curves A. as well as the other curves of Figs. 9. 10 and ll, are drawn to scale and the maximum value of the water velocity during the pulsion period is approximately 8.5 inches per second and the maximum absolute value of the suction period I is approximately 4.7 inches per second.

Considering curve A of Fig. 10 and comparing.

it with the half cycle sine curves C and D, it is seen that during the first part of period a curve A rises at a rate less rapid than the sine curve C. 0.1 stated in a different manner, the magnitude of the velocity is less than that of the sine curve C. During period b, the velocity is less than that of sine curve C while the slope is greater. The maximum amplitude of curve A appears near the center of period c and thus at a time later than the maximum amplitude of sine curve C. During the latter part of period c and during period at, the velocity is greater than that of the sine curve C and the slopeis greater than that of said sine curve C. It is also to be noted that the top portion of curve A has a smaller radius of curvature than the sine wave C, or in other words, persists during a shorter time interval than does the sine curve C.

Considering the suction period, in which absolute values are considered, during period c .and most of period 1, the slope is greater than that of sine curve D and the velocities greater. The maximum value occurs near the center of period I. During the latter part of period 3 and substantially the whole of period g, the velocity is much less than the sine curve D and has a greater slope. An abrupt change in slope is seen at the end of period 9 followed by a velocity and slope both smaller than the sine curve D during than that of sine curve C. During period b, the

velocity follows the sine curve rather closely. The maximum amplitude of the curve A substantially coincides with that of the sine curve C. During period c the slope is greater than that of sine curve C and the velocity less. During period (I the velocity is less than that of C and the slope less. It is again to be noted that the top portion of curve A has a smaller radius of curvatu're than the sine wave C, or in other words, persists during a shorter time interval than does the sine curve C. Considering the suction period, it is seen that it is essentially the same as that of Fig. 10 and the description of said Fig. 10 may apply with equal force to Fig. 11. The maximum value of the pulsion velocity is approximately 7.2 inches per second, and the maximum absolute value of the suction period is approximately 5.6 inches per second.

As a general statement respecting each of the curves A of Figs. 9, 10 and 11 many time-velocity curve representative of my method of operation, it may be stated that in comparing .the pulsion period with a half cycle of a sine curve having a maximum amplitude and a frequency equal to the maximum amplitude and frequency thereof and comparing the suction period with a half cycle of a sine curve having a maximum amplitude and a frequency equal to the maximum amplitude, in absolute value, and frequency thereof and dividing each half sine curve into four equal time intervals, designated a, b, c, d and e, f, g, h, respectively, the following conditions will maintain, though certain exceptions may be encountered. During period a and particularly during the first part thereof, the magnitude of the velocity will be small as compared with the sine curve or the rate of increase of velocity will be small. This characteristic is almost always obtained. During period b, the magnitude of the velocity may be greater or less than the sine curve but quite generally the slope thereof will be greater, at least over the first half of the period. During period c, the velocity may be greater or less than the sine curve but if the velocity is greater the slope will be less and if the velocity is lower the slope will be equal to or greater on the average. Period (1 may vary considerably depending on period c. In addition, it is quite uniform that the top of the curve, representing about onefourth of the ordinates from the top down, has

a smaller radius of curvature than the sine curve,

or in other words, persists over a smaller time interval than the sine curve. During period e, the velocity is greater, in absolute value, than the sine curve and the slope is greater. The peak of the suction stroke quite generally appears in period I, or at a time in advance of the peak of the sine curve. During period 9, the absolute value of the velocity is smaller than the sine curve and the slope is greater. Also near the end of this period, the slope decreases rather abruptly. During period h the velocity is smaller than the sine wave and the slope quite generally smaller. It is also to be noted that the pulsion and suction periods need not be of equal time duration, though they may be, and in the illustrations given they are not.

In the illustration of Fig. 9, the pulsion period is much shorter than the suction period; in the illustration of Fig. 10, the pulsion period is somewhat long-er than the suction period; while in the illustration of Fig. 11, they are nearly equal, the suction period being slightly longer.

Near the bottom of each of the Figs. 9, 10 and 11, there is indicated along line G-G, by the numerals I through 9, the extent of each of the bed conditions illustrated by Fig. 12 as these bed conditions occur under the action of the water passing through the sieve or screen according to the time-velocity curve A of that figure. A discussion of the water action and the consequent bed condition and stratifying action which takes place withcurve A of Fig. 9 will be representative of the entire group, due account being taken in each case as to the position of the bed condition indicating numerals. In this consideration, I set forth, not only my belief as to the bed condition as it changes under the control of the jigging fluid during each cycle of operation, but my theory as to the reasons why this jigging cycle produces an improved result. However, it is to be understood that I am not bound by this theory, for whatever the reason may be, and regardless of the mode of stratification, it is known that the particular cycle of operation illustrated by the time-velocity water curves illustrated, produces an improved and desirable jiggling cycle.

In a given feed, stratification of the coarser sizes according to specific gravity, is primarily effected by the pulsion periods; the stratification of the finer sizes must be effected by the suction periods. In other words, properly used, the suction periods make it possible to treat a large range of sizes in one operation. However, the suction periods are only effective between the time the water starts downward and the time the bed closes. During this short interval, the separation is according to specific gravity and without regard to the size and shape of the particles being treated. If, during the pulsion periods which occur intermittently between the suction periods, the bed is held in a condition of mobility for a longer time than necessary for the particles to become free to move; that is, if there is any sustained mobility in any part of the bed, the jig in effect becomes an upward current classifier and stratifies fine refuse with coarse particles of coal. To whatever extent this occurs, it nullifies the effect of the separation according to specific gravity obtained in the suction periods. The result is a great loss in capacity in the jig, or the actual discharge of the finer particles of refuse with the washed coal. In my improved method, the pulsion period is effective to give a nearly simultaneous opening of the whole bed presenting a condition of full mobility followed by a quick closing of the bed and thus avoiding in a large measure the deleterious effects of any sustained period of bed mobility;

As seen in said Fig. 9, during the first part of period a the water velocity upwardly through the screen increases slowly and is less than the sine curve C. This is followed by an increasing rate arsasvc of flow during the latter part of said period.

I The first part with the slow increase in velocity,

partially opens the top of the bed as indicated by the bed condition character I. However, before the bed can open, the increased rate of water velocity lifts the entire bed as a whole oil the the water continues to increase in velocity, it

lifts the upper'layers further and the bottom layers continue to drop off the bed. This continues further, as indicated by bed characters t and 5, until the bed is entirely open as indicated by bed character 6. It is to be noted that the full mobile condition as indicated by bed character 6 is indicated as appearing on the latter part of period c, or after the maximum velocity is reached. 'It may be that this condition is realized much sooner, for example, near the end of period b or before the maximum velocity is reached. However, the entire bed opening, particularly from bed condition 3 to bed condition 6, or full mobility, takes place in a rather short time interval.

The deceleration of the fluid, or decrease in velocity after the peak velocity is reached, is more rapid than the sine curve, as is seen during period c and the first part of period d; This'is effective to reduce to a minimum the separation as an upward current classifier which tends to stratify 'the fine refuse with the larger particles of coal. It also allows opening of any top layers which were possibly not previously completely opened. It is also to be noted that the rapid decrease in velocity after the peak velocity is reached has as an incident the maintaining of the higher pulsion velocities for a relatively short time.

During period e, which is the first part of the suction period, and particularly during the first part thereof, the fluidflows down through the screen under the'pull of gravity. The bed is in the condition indicated by bed character I, with the bottom layers closed and most of the top open. During this part of the period, there is a maximum separation of particles accgrding to specific gravity. With the-bed completely mobile at the beginning of this period, this period reaches its maximum eflectiveness. This action continues into periods 1 and g as indicated by bed character 8 until a distinct downward pull is caused in the topmost layers of the bed. After this period has reached its maximum effectiveness, toward the end of period 9, the downward flow of current is sharply reduced to prevent too solid a packing of the bed and the bed closes during the latter part of period 9' and during period it. The increased downward velocities during period c and part of period I is necessary inorder to have strong suction throughout the bed and to reach the topmost layers. However, to prevent extreme packing of the bed which would result in an undesired lifting of the entire bed during the first part of period a of the pulsionperiod, it is desirable to retard the velocity of the fluid during the latter part of the suction period or during period It.

As has been above stated, the time-velocity fluid curves A of Figs. 9, l and 11 may be ob- I tained by either an air operated water jig of the type illustrated by Figs. 1 "and 2 or a cam operated water jigof the type illustrated by Figs. 3 and 4. Where the latter is used a cam is formed to produce the desired time-velocity curve A in the manner above described in connection with curve F of Fig. 9. Where an air controlled jig is used, designated generally in the art by the name Baum type, the curves A of Figs. 9, 10 and ii may be obtained by setting the valve shown in detail in Figs. 5 and 6 as indicated by the table hereinabove and on Figs. 9, and 11. This setting of water, air pressure, air volumeand stroke is for a tonnage of 4000 pounds per square foot per hour of bituminous or soft slack coal of %-0 size range. The same water volume would hold for a cam type jig. Certain variations may be necessary with different coals and particularly if a different size rangeor a difl'erent ton nage is used. Knowledge of these. variations will be easily acquired by skilled operators and will, of course, be made in carrying out the method as employed under conditions not identical with the illustrations given. With high .peak velocities required for coarse coal it may be necessary to operate the jig at lower speeds to give ample timefor the bed to open. This is particularly necessary on the cam produced stroke.

Referring again to the curve A of Fig. 9 as illustrative of all of the A curves and considering particularly the four periods of operation of the air valve, comprising inlet or air admission, -eX-- pansion, exhaust and compression, the resulting pressures in the air chamber as indicated by curve B and the resulting time velocity fluid or -water curve A; it is seen that the velocity is zero at substantially the "instant the valve starts to open, but the pressure in the air chamber is appreciable. The water reaches its maximum velocity during the air admission or inlet period and .starts to drop off while this valve is still open.

The maximum air chamber pressure is reached before the-maximum.fluid velocity is reached. During the expansion period, when both inlet and exhaust valves are closed, the water velocity decreases rapidly at least until the latter part thereof. During this decrease in velocity, the air chamber pressures drop and may, as in Fig. 9, actually become slightly negative. This means the continued upward movement of water which takes place after the air chamber is sealed, actually produces a negative pressure in said chamber. maximum fluid velocity and a short pulsion period as found in Fig. 9. The air pressures do not become negative in Figs. 10 and 11 where the pulsion period is longer and the maximum velocity is lower. In Fig. 9, the pulsion period ends at approximately the end of the expansion period. The suction period reaches its maximum downward velocity during the exhaust period, when the exhaust ports are open, during which time the chamber pressure is zero, as it is open pression period, with both valves closed, then This is a characteristic of a highoccurs and forms an air cushion for the final I downward movement of the fluid, preventing severe packing of the bed. During this compression period, the pressure in the air chamber gradually rises.

It may be noted that in the curve A of Fig. 10 the. latter part of the pulsion stroke is during an exhaust period with a consequent very rapid rate of. deceleration of fluid flow. It is also who noted that in this case the inlet or air admission period starts before the suction period is entirely ended. In some cases, it has been found that the compression period is effective not only to complete the suction period but actually starts a pulsion period before the air admission period is started.

The rate of opening and closing of the inlet and exhaust ports are indicated by curve E of Figs. 9, 10 and 11. These rates, particularly the rate of opening of the inlet ports during air admission, are effective to control the shape of the curve A. It is obvious that by controlling the rate of opening and closing of the inlet and exhaust ports, and by varying the relative periods of air inlet or admission, expansion, exhaust and compression, time-velocity fluid curves A, of a large variety of shapes may be obtained. This, in itself, is an important feature of my invention. The curves are also effected by the rate of water inlet, for by supplying suflicient water the suctiorr stroke may be greatly reduced or even eliminated. The maximum upward fluid velocity may also be regulated by controlling the cycle of the air control valve and also by controlling the air pressure in the air reservoir. The speed of the jig or the frequency may be varied within wide limits. The range actually used has been between and 150 cycles per minute.

Instead of employing the apparatus of Figs. 3 and 4 to produce the desired time-velocity curve A, the apparatus disclosed in the application of Byron M. Bird and Ernst F. Muller for Apparatus for treating mineral materials, Serial No. 736,442,

filed July 22, 1934, may be employed.

Obviously those skilled in the art may make various changes in the details and arrangement ,of parts without departing from the spirit and scope of the invention as defined by the claims hereto .appended, and I wish therefore not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment of. my invention, what I'desire to secure by Letters Patentof the United States is:

1. The method of jigging by cyclically controlling the application of fluid under pressureto a chamber forming one leg of a U-shaped tank carrying a perforate bed supporting plate in the other leg thereof, said tank containing a jigging liquid adapted to be moved relative to said plate, each cycle of which constitutes 360 degrees and comprises admitting a fluid under pressure to said chamber for a period of said cycle less than 130 degrees to force said jigging liquid upward through said plate, discontinuing the admission of fluid to said chamber, maintaining said chamber sealed for a relatively long period of said cycle and thereafter opening said chamber to reduce the pressure therein for a period.

2. The method of jigging by cyclically controli' ling the application of fluid under pressure to.

a chamber containing a jigging liquid adapted to be moved relative to a bed of materiaL- each cycle of which constitutes 360 degrees and comprises admitting a fluid under pressure to said chamber for a period of said cycle less' than 150 degrees to force said jigging liquid upward through said bed, discontinuing the admission of fluid to said chamber, maintaining said chamber sealed for a relatively long period of said cycle and thereafter opening said chamber to reduce the pressuretherein for a period.

3. The method of jigging by cyclically controlling the application of fluid under pressure to a chamber containing a jigging liquid adapted to be moved relative to a bed of material, each cycle of which constitutes 360 degrees and comprises, admitting a fluid under pressure to said chamber for a period of a cycle to force said jigging liquid upward through said bed, discontinuing the admission of fluid to said chamber, maintaining said chamber sealed for a period which may be variably determined at a value be tween 30 and 150 degrees of said cycle and thereafter opening said chamber to reduce said pressure for a period.

4. The method of jigging by cyclically controlling the application of fluid under pressure to a chamber forming one leg of a U-shaped tank carrying a perforate bed supporting plate in the other leg thereof, said tank containing a jigging liquid adapted to be moved relative to said plate, each cycle of which constitutes 360 degrees and comprises, admitting a fluid under pressure to said chamber for a period of a cycle to force said jigging liquid upward through said plate, discontinuing the admission of fluid to said chamber, maintaining said chamber sealed for a period which may be variably adjusted at a value from 20 to 150 degrees of said cycle and thereafter opening said chamber to reduce said pressure for a period.

5. The method of jigging by cyclically controlling the application of fluid under pressure to a chamber containing a jigging liquid adapted to be moved relative to a bed of material, each cycle of which constitutes 360 degrees and comprises, admitting a fluid under pressure to said chamber for a period of a cycle to force said jigging liquid upward through said bed, discontinuing the admission of fluid to said chamber, maintaining said chamber sealed for a period of not less than 30 degrees of said cycle and thereafter opening said chamber to reduce said pressure for a period.

6. The method of jigging by cyclically controlling the application of fluid under pressure to a chamber, containing a jigging liquid adapted to be moved relative to a bed of materials, each cycle of which constitutes ,360 degrees and comprises, admitting a fluid under pressure to said chamber for a period of a cycle to force said jigging liquid upward through said bed, discontinuing the admission of fluid to said chamber, maintaining said chamber sealed for a period of not less' than 60 degrees of said cycle and thereafter opening said chamber to reduce said pressure for a period.

'7. The method of jigging by cyclically controlling the appllcation of fluid under pressure to a chamber containing a jigging liquid adapted to .be moved relative to a bed of material, each cycle of which constitutes 360 degrees and comprises, admitting a fluid under pressure to said chamberfor a period of a cycle to force said jigging liquid upward through said bed, discontinuing .the admission of fluid to said chamber, maintaining said chamber sealed for a period of not less than 90 degrees of said cycle and there- 'liquid adapted to be moved relative to said plate,

each cycle of which constitutes 360 degrees and comprises, admitting a fluid under pressure to of a cycle of 360 degrees, thereafter opening said said chamber for a period of a cycle to force said jigging liquid upward through said plate, discontinuing the admission of fluid to said chamber, maintaining said chamber sealed for a period of not less than 120 degrees of said cycle and thereafter opening said chamber to reduce said pressure for a period.

EhThe method of jigging by cyclically controlling the applicationof fluid under pressure to a chamber containing a jigging liquid to be moved relative to a bed of material, each cycle of which comprises, admitting fluid under pressure to said chamber, sealing said chamber against air ingress or egress, opening said chamber to reduce the pressure therein and again sealing said chamber against air ingress or egress, the periods during which said chamber is sealed being variably determined at a valuebetween 30 and 150 degrees of a cycle of 360 degrees.

10. The methodof jigging by cyclically controlling the application of fluid under pressure to a chamber containing a jigging liquid to be moved relative to a bed of material, each cycle of which comprises, admitting fluid under pressure to said chamber, sealing said chamber against air ingress or egress, opening said chamber to reduce the pressure therein and again sealing said chamber against air ingress or egress, the periods during which said chamber is sealed being not less than 30 degrees of a cycle of 360 degrees. 11. The method of jigging by cyclically controlling the application of fluid under pressure to a chamber containing a jigging liquid to be moved relative to a bed of material. each cycle of which comprises, admitting fluid under pressure to said chamber, sealing said chamber against air ingress or egress, opening said chamber to reduce the pressure therein and again sealing said chamber against air ingress or egress,

the periods during which said chamber is sealed being not less than degrees of a cycle of 360 degrees.

12. The method of jigging by cyclically con trolling the application of fluid under pressure to a chamber containing a jigging liquid to be moved relative to a bed of material, each cycle of which comprises, admitting fluid under pressure to said chamber, sealing said chamber.

against air ingress or egress, opening said chamber to reduce the pressure therein and again sealing said chamber against air ingress or egress, the periods during which said chamber is sealed being not less than degrees of a cycle of 360 degrees.

13. The method of jigging by cyclicallycontrolling the application of fluid under pressure to a chamber containing a jigging liquid to be moved relative to a bed of material, each cycle of which comprises, admitting fluid under pressure to said chamber, sealing said chamber against air ingress or egress, opening said chamher to reduce the pressure therein and again sealing said chamber against air ingress or egress, the periods during which said chamber is sealed being not less than degrees of a cycle of 360 degrees.

14. The method of cleaning coal which comprises subjecting a bed of raw coal to a jigging operation by controlling the application of fluid under pressure to a chamber containing a jigging liquid to be moved relative to said bed of coal, comprising cyclically admitting fluid under pressure to said chamber for a period, sealing said chamber for a period of not less than 120 degrees terms on top,

chamber to reduce the strata, and directing said refuse and coal into different channels.

15. The method of cleaning coal which comprises subjecting a bed of raw coal to a jigging operation by controlling the application of fluid under pressure to a chamber containing a jigging liquid to be moved relative to said bed of coal, comprising cyclically admitting fluid under pressure to said chamber for a period, sealing said chamber for a predetermined period which is at least half as long as said admission period, thereafter opening said chamber to reduce the pressure therein, thereby stratifying the clean coal and refuse in different strata, and separating said strata.

16. The method of separating materials of different densities by cyclically varying the movement of a fluid with respect to a perforate support carrying a bed of said materials of different densities to stratify said bed, each cycle of which may be represented by a time-velocity curve having successive pulsion and suction periods in which the curve of the pulsion period fairly closely follows a half-sine wave of equal maximum value and time except for the following variations; (1) the slope thereof is lower at first and then increases rapidly to a higher value as the curve peak is approached, (2) the crown of the curve has a smaller curvature, (3) the slope of the curve immediately after the crown is greater; and in which the curve of the suction period roughly follows a negative half-sine wave of equal maximum absolute value and time except that during the final part thereof it is considerably less than said half-sine wave; thereby stratifying said bed of materials into strata of different specific gravities with the high gravity materials on the bottom and the low gravity maand directing the stratified high and low gravity materials along different paths.

17. The method of jigging by cyclically varying the movement of a fluid with respect to a perforate support carrying a bed of materials of different densities to stratify said bed, each cycle of which may be represented by a time-velocity curve having successive pulsion and suction periods in which the curve of the pulsion period siderably less than said half-sine wave, and in which the bed of materialsbeccmes completely mobile at a time which is reached after the peak velocity of the pulsion period is passed; thereby stratifying said bed of materials according to specific gravities with the high gravity materials in the bottom stratum and the low gravity materials in the top stratuni, and directing said pressure therein, thereby stratifying the clean coal and refuse in different stratified materials along separate paths to efl'ect a separation thereof.

BYRON M. BIRD. 

